1. Field of the Invention
The present invention relates to an integrated circuit memory wherein a plurality of integrated circuits (hereinafter referred to as "IC") of different types are combined into hybrid form, and more specifically to an integrated circuit memory which is applied, for example, to a dialogue type machine tool and rewrites information of various sorts regarding works detected by sensors, or which is applied, for example, to an identification card and rewrites information to be updated into a new one, so that permanent storage information and rewriting storage information are stored in respective memory units and each memory unit is integrated into one chip or one module.
2. Description of the Prior Art
In the prior art, a memory integrated into one chip or one module is exemplified in random access memory (hereinafter referred to as "RAM") having feature in difference of access method or read only memory (hereinafter referred to as "ROM") having feature in memory holding state. Particularly the ROM is exemplified in a mask ROM for storing information which must be fixedly held, and a programmable ROM (hereinafter referred to as "PROM") which can set to change the stored information by a write operation. The PROM includes, for example, a fuse type PROM where erase or rewrite is impossible after the information has been written once, a diode junction destruction type PROM being a memory fixing type, an erasable PROM (hereinafter referred to as "EPROM") where erase and rewrite can be performed repeatedly, an electrical alterable PROM (hereinafter referred to as "EAPROM") being a memory charging type, and the like. The EPROM performs erase of the stored information by means of irradiation by ultraviolet rays or the like, whereas the EAPROM performs erase or rewrite of the stored information electrically and is also called an electrically erasable PROM hereinafter referred to as "E.sup.2 PROM"). These IC memories are tabulated in TAB. 1 described on next page.
Each memory element may be used with any portion of electronic equipment corresponding to its use, function or the like. Regarding manufacturing of the IC memory, one chip or one module is formed, for example, through (1) thermal oxidation process, (2) thermal diffusion process, (3) epitaxial layer growth accelerating process, (4) window making process, (5) wiring process, (6) nitride film coating process, (7) bonding process, (8) packaging process, thereby the IC memory having constant function and constant capacity is completed.
TABLE 1 __________________________________________________________________________ ##STR1## ##STR2## __________________________________________________________________________
The storage function of these IC memories will be described. In the MASKROM and the PROM, once information data is written the information cannot be rewritten. In the EPROM, once information is written, the written information can be erased and then the information can be written. In the RAM, information can be written or rewritten freely, but if the power source is interrupted the written information is erased. In the E.sup.2 PROM, information can be written electrically, and even if the power source is interrupted the written information can be held as it is.
In general, in order to constitute a memory, IC memories each having single function such as RAM, MASKROM, PROM, EPROM, E.sup.2 PROM are used in suitable combination, and assembled together with a peripheral device to control these memories on a substrate so that required function is provided.
The IC memories assembled as above described in the prior art are assembled as external memory elements of a numerical control machine tool for example, and perform storage, holding and update of various values such as length of a work, diameter, cutting speed, life of a tool, and the like. An example of such IC memories is disclosed in "Tool Dialogue System" in "Search Report of Trend in Basic Studies" March 1985, pp 156-157, by "Japan Machine Tool Buiders' Association".
Since the memory in the prior art is constituted as above described, IC memories each having a single function must be used in combination and assembled on a substrate; thereby the memory becomes large-scale and expensive. Moreover, since utilization in assembling in an identification card or an identification module is difficult, such memory in the prior art cannot be applied to products which are compact and portable.
Memory cell arrays having the required functions among required elements of the above-mentioned IC memories may be combined into one chip. However, for example, the read write memory (RWM) and the ROM are different from each other in set voltage, drive voltage or reset voltage and therefore cannot use the same address register. Consequently, even if the IC memories are formed into one chip, respective system constitutions are required to perform the drive control and therefore the circuit constitution at the side of the terminal end machine is complicated and the benefits of one-chip forming cannot be obtained.